Tuesday, August 02, 2005

SetUp and Teardown are still not good

At dinner tonight we had a wonderful discussion about testing. One topic was why SetUp and Teardown (S&T) are wrong, which I've previously blogged about. My biggest issue with S&T is that it's used to enforce DRY at the expense of readability.

Image a test that did not use S&T, it would do exactly what you wanted all in one test method (with possible helper private methods). There would be no where else to look for logic, variable declarations, or mock verifies. Wouldn't it be nice if all tests were that readable.

Unfortunately, somewhere along the way we started sacrificing readability. Also, we started blindly following rules like DRY without considering context. Sure, DRY is a great rule, but what if the duplicate code only appears within the class? What if it were only 1 line, like a variable declaration? Do you really gain anything by abstracting it to a SetUp method? Yes, you gain the ability to only make changes in one place. But, if you could make the change in one place, ensure that it changed everything correctly, and not sacrafice readability. Does this magical feature exist? Find and Replace (in this file/class only). What about more than 1 line of duplicate code? Once upon a time this was handled with private methods and the flow of a test was easy to follow. Times were simpler then, but now we do "the simplest thing that could possibly work", or do we?

Tests are procedural by naturue. Allowing developers to read tests in a procedural manner just makes sense.